Conventionally, III nitride semiconductors made of compounds of N with Al, Ga, In, and the like are used as materials for ultraviolet light-emitting devices. III nitride semiconductors made of high-Al-content AlGaN are particularly used for ultraviolet light-emitting devices or deep ultraviolet light light-emitting devices (DUV-LED) emitting light at a wavelength of 300 nm or less.
Examples of the characteristics required of a light-emitting device include high external quantum efficiency properties and low resistance properties. JP 2010-205767 A (PTL 1) describes that a layer serving as an energy barrier for electrons, which is called an electron blocking layer, is formed between a light emitting layer having a quantum well structure and a p-type cladding layer, thereby improving the light emission efficiency.